<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>常量</title>
</head>

<body>
  <img src="./js-课堂笔记img/let-var-const.png" alt="">
  <script>
    
    //1. 常量 不允许更改值
    // const PI = 3.14
    // console.log(PI);
    // PI = 3.15
    // console.log(PI); //报错 赋值给常量变量

    //2. 常量声明的时候必须赋值
    // const PI // 报错
  </script>
</body>
</html>